New Approach of Deterministic Key Pre-distribution Scheme Using Triangle Free Quasi Symmetric Designs

A wireless sensor network (WSN) consists of tiny autonomous sensor nodes with some constraints. There are organizations having moderately necessitates of these kind of networks. So, security become an indispensable concern in WSN, due to potential adversaries. To overcome the security problem, keys are pre-loaded to the nodes before deployment. Among all key distribution schemes, deterministic key pre-distribution scheme (KPS) using combinatorial design is efficient regarding security aspect. In this paper, a deterministic approach, based on combinatorial design, for key assignment before the network deployment has been presented. Here the quasi-symmetric design which is of triangle-free is being used to present the new KPS for sensor networks. Due to this approach each sensor node either will contain a key-chain or will communicate through a key-path. This will improve the resiliency and achieve the sufficient level of security in the network. This design can also be used when a large number of nodes are being deployed in WSN

Physico-chemical parameters of Seepage stream at Kushaha area

Physico-chemical parameters of the Seepage stream of Kushaha area were studied for two years from July, 2002-June, 2004, once in every month at regular intervals. The monthly data were pooled in seasonal value. The maximum air temperature was recorded in rainy season during first year study period (July, 2002 to June, 2003) but in the second year study period (July, 2003 to June 2004) it was maximum in summer season. Water temperature was maximum in summer and lowest in winter season. Transparency, PH, dissolved oxygen, total alkalinity, total hardness, chloride were recorded maximum in winter season. Free carbondioxide, and biological oxygen demand was maximum in summer season. The minimum transparency, total alkalinity, total hardness and chloride were recorded in rainy season. Dissolved oxygen, and PH, were minimum in summer season. The minimum carbondioxide and BOD were recorded in winter season. Air temperature, water temperature, free carbondioxide, biological oxygen demand showed positive and significant correlation with each other. Similarly, transparency, PH, total alkalinity, total hardness, chloride, showed positive and significant correlation with each other. Dissolved oxygen showed positive and significant correlation with pH, total alkalinity, total hardness and chloride. Keywords: Physico- chemical parameters; seepage system DOI: http://dx.doi.org/10.3126/bibechana.v8i0.5697 BIBECHANA 2012; 8: 105-11

Physico-chemical parameters of Seepage stream at Kushaha area

Physico-chemical parameters of the Seepage stream of Kushaha area were studied for two years from July, 2002-June, 2004, once in every month at regular intervals. The monthly data were pooled in seasonal value. The maximum air temperature was recorded in rainy season during first year study period (July, 2002 to June, 2003) but in the second year study period (July, 2003 to June 2004) it was maximum in summer season. Water temperature was maximum in summer and lowest in winter season. Transparency, PH, dissolved oxygen, total alkalinity, total hardness, chloride were recorded maximum in winter season. Free carbondioxide, and biological oxygen demand was maximum in summer season. The minimum transparency, total alkalinity, total hardness and chloride were recorded in rainy season. Dissolved oxygen, and PH, were minimum in summer season. The minimum carbondioxide and BOD were recorded in winter season. Air temperature, water temperature, free carbondioxide, biological oxygen demand showed positive and significant correlation with each other. Similarly, transparency, PH, total alkalinity, total hardness, chloride, showed positive and significant correlation with each other. Dissolved oxygen showed positive and significant correlation with pH, total alkalinity, total hardness and chloride. Keywords: Physico- chemical parameters; seepage system DOI: http://dx.doi.org/10.3126/bibechana.v8i0.5697 BIBECHANA 2012; 8: 105-11

BRAZILIAN ARCHIVES OF BIOLOGY AND TECHNOLOGY A N I N T E R N A T I O N A L J O U R N A L Hepatic Cytochrome P450 as Biomarkers of Cypermethrin Toxicity in Freshwater Teleost, Channa punctatus (Bloch)

ABSTRACT In this study, Channa punctatus was treated with sub-lethal concentration of cypermethrin (6.

Dynamics of asymmetric intraguild predation with time lags in reproduction and maturation

A three dimensional (3D) stage-structured predator–prey model is proposed and analyzed to study the effect of intraguild predation with harvesting of the adult species. Time lags in reproduction and maturation of the organism are introduced in the system and conditions for local asymptotic stability of steady states of delay differential forms of the ODE model are derived. The length of the delay preserving the stability is also estimated. Moreover, it is shown that the system undergoes a Hopf bifurcation when the time lags cross certain critical values. The stability and direction of the Hopf bifurcations are determined by applying the normal form method and the center manifold theory. Computer simulations have been carried out to illustrate various analytical results

Potential effects of invasive Pterois volitans in coral reefs

The invasion of predatory lionfish (Pterois volitans) represents a major threat to the western Atlantic coral reef ecosystems. The proliferation of venomous, fast reproducing and aggressive P. volitans in coral reefs causes severe declines in the abundance and diversity of reef herbivores. There is also widespread cannibalism amongst P. volitans populations. A mathematical model is proposed to study the effects of predation on the biomass of herbivorous reef fishes by considering two life stages and intraguild predation of P. volitans population with harvesting of adult P. volitans. The system undergoes a supercritical Hopf bifurcation when the invasiveness of P. volitans crosses a certain critical value. It is observed that cannibalism of P. volitans induces stability in the system even with high invasiveness of adult P. volitans. The dynamic instability of the system due to higher invasiveness of P. volitans can be controlled by increasing the rate of harvesting of P. volitans. It is also proven that P. volitans goes extinct when the harvest rate is greater than some critical threshold value. These results indicate that the dynamical behaviour of the model is very sensitive to the harvesting of P. volitans, which in turn is useful in the conservation of reef herbivores